21878833851 has 12 divisors (see below), whose sum is σ = 36117440112. Its totient is φ = 12502190736.

The previous prime is 21878833799. The next prime is 21878833871. The reversal of 21878833851 is 15833887812.

21878833851 is a `hidden beast` number, since 2 + 187 + 8 + 83 + 385 + 1 = 666.

It is not a de Polignac number, because 21878833851 - 2⁶ = 21878833787 is a prime.

It is a Smith number, since the sum of its digits (54) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (21878833871) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 173641476 + ... + 173641601.

It is an arithmetic number, because the mean of its divisors is an integer number (3009786676).

Almost surely, 2^21878833851 is an apocalyptic number.

21878833851 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

21878833851 is a deficient number, since it is larger than the sum of its proper divisors (14238606261).

21878833851 is a wasteful number, since it uses less digits than its factorization.

21878833851 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 347283090 (or 347283087 counting only the distinct ones).

The product of its digits is 2580480, while the sum is 54.

The spelling of 21878833851 in words is "twenty-one billion, eight hundred seventy-eight million, eight hundred thirty-three thousand, eight hundred fifty-one".